Implement prefer-template tslint rule

contracts/core/test/exchange/signature_validator.ts

@@ -135,7 +135,7 @@ describe('MixinSignatureValidator', () => {
 
         it('should revert when signature type is unsupported', async () => {
             const unsupportedSignatureType = SignatureType.NSignatureTypes;
-            const unsupportedSignatureHex = '0x' + Buffer.from([unsupportedSignatureType]).toString('hex');
+            const unsupportedSignatureHex = `0x${Buffer.from([unsupportedSignatureType]).toString('hex')}`;
             const orderHashHex = orderHashUtils.getOrderHashHex(signedOrder);
             return expectContractCallFailedAsync(
                 signatureValidator.publicIsValidSignature.callAsync(
@@ -148,7 +148,7 @@ describe('MixinSignatureValidator', () => {
         });
 
         it('should revert when SignatureType=Illegal', async () => {
-            const unsupportedSignatureHex = '0x' + Buffer.from([SignatureType.Illegal]).toString('hex');
+            const unsupportedSignatureHex = `0x${Buffer.from([SignatureType.Illegal]).toString('hex')}`;
             const orderHashHex = orderHashUtils.getOrderHashHex(signedOrder);
             return expectContractCallFailedAsync(
                 signatureValidator.publicIsValidSignature.callAsync(
@@ -161,7 +161,7 @@ describe('MixinSignatureValidator', () => {
         });
 
         it('should return false when SignatureType=Invalid and signature has a length of zero', async () => {
-            const signatureHex = '0x' + Buffer.from([SignatureType.Invalid]).toString('hex');
+            const signatureHex = `0x${Buffer.from([SignatureType.Invalid]).toString('hex')}`;
             const orderHashHex = orderHashUtils.getOrderHashHex(signedOrder);
             const isValidSignature = await signatureValidator.publicIsValidSignature.callAsync(
                 orderHashHex,

contracts/core/test/utils/exchange_wrapper.ts

@@ -228,7 +228,7 @@ export class ExchangeWrapper {
         return orderEpoch;
     }
     public async getOrderInfoAsync(signedOrder: SignedOrder): Promise<OrderInfo> {
-        const orderInfo = (await this._exchange.getOrderInfo.callAsync(signedOrder)) as OrderInfo;
+        const orderInfo = await this._exchange.getOrderInfo.callAsync(signedOrder);
         return orderInfo;
     }
     public async getOrdersInfoAsync(signedOrders: SignedOrder[]): Promise<OrderInfo[]> {

contracts/test-utils/src/assertions.ts

@@ -137,7 +137,7 @@ export async function expectTransactionFailedWithoutReasonAsync(p: sendTransacti
                 // directly.
                 txReceiptStatus = result.status;
             } else {
-                throw new Error('Unexpected result type: ' + typeof result);
+                throw new Error(`Unexpected result type: ${typeof result}`);
             }
             expect(_.toString(txReceiptStatus)).to.equal(
                 '0',

contracts/utils/test/lib_bytes.ts

@@ -25,7 +25,7 @@ const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
 
 // BUG: Ideally we would use Buffer.from(memory).toString('hex')
 // https://github.com/Microsoft/TypeScript/issues/23155
-const toHex = (buf: Uint8Array): string => buf.reduce((a, v) => a + ('00' + v.toString(16)).slice(-2), '0x');
+const toHex = (buf: Uint8Array): string => buf.reduce((a, v) => a + `00${v.toString(16)}`.slice(-2), '0x');
 
 const fromHex = (str: string): Uint8Array => Uint8Array.from(Buffer.from(str.slice(2), 'hex'));
 

packages/monorepo-scripts/src/test_installation.ts

@@ -98,7 +98,7 @@ async function testInstallPackageAsync(
     const lastChangelogVersion = JSON.parse(fs.readFileSync(changelogPath).toString())[0].version;
     const packageName = installablePackage.packageJson.name;
     utils.log(`Testing ${packageName}@${lastChangelogVersion}`);
-    const packageDirName = path.join(...(packageName + '-test').split('/'));
+    const packageDirName = path.join(...`${packageName}-test`.split('/'));
     // NOTE(fabio): The `testDirectory` needs to be somewhere **outside** the monorepo root directory.
     // Otherwise, it will have access to the hoisted `node_modules` directory and the Typescript missing
     // type errors will not be caught.

packages/order-utils/test/order_hash_test.ts

@@ -70,7 +70,7 @@ describe('Order hashing', () => {
         });
         it('returns true if order hash is correct', () => {
             const orderHashLength = 65;
-            const isValid = orderHashUtils.isValidOrderHash('0x' + Array(orderHashLength).join('0'));
+            const isValid = orderHashUtils.isValidOrderHash(`0x${Array(orderHashLength).join('0')}`);
             expect(isValid).to.be.true();
         });
     });

packages/pipeline/src/data_sources/bloxy/index.ts

@@ -116,7 +116,7 @@ export class BloxySource {
             },
         });
         if (isError(resp.data)) {
-            throw new Error('Error in Bloxy API response: ' + resp.data.error);
+            throw new Error(`Error in Bloxy API response: ${resp.data.error}`);
         }
         return resp.data;
     }

packages/pipeline/src/data_sources/paradex/index.ts

@@ -1,9 +1,9 @@
 import { fetchAsync, logUtils } from '@0x/utils';
 
 const PARADEX_BASE_URL = 'https://api.paradex.io/consumer/v0';
-const ACTIVE_MARKETS_URL = PARADEX_BASE_URL + '/markets';
+const ACTIVE_MARKETS_URL = `${PARADEX_BASE_URL}/markets`;
-const ORDERBOOK_ENDPOINT = PARADEX_BASE_URL + '/orderbook';
+const ORDERBOOK_ENDPOINT = `${PARADEX_BASE_URL}/orderbook`;
-const TOKEN_INFO_ENDPOINT = PARADEX_BASE_URL + '/tokens';
+const TOKEN_INFO_ENDPOINT = `${PARADEX_BASE_URL}/tokens`;
 export const PARADEX_SOURCE = 'paradex';
 
 export type ParadexActiveMarketsResponse = ParadexMarket[];

packages/sol-compiler/src/compiler.ts

@@ -400,7 +400,7 @@ export class Compiler {
                  * while others are absolute ("Token.sol", "@0x/contracts/Wallet.sol")
                  * And we need to append the base path for relative imports.
                  */
-                importPath = path.resolve('/' + contractFolder, importPath).replace('/', '');
+                importPath = path.resolve(`/${contractFolder}`, importPath).replace('/', '');
             }
 
             if (_.isUndefined(sourcesToAppendTo[importPath])) {

packages/tslint-config/tslint.json

@@ -92,6 +92,7 @@
         "prefer-function-over-method": true,
         "prefer-object-spread": true,
         "prefer-readonly": true,
+        "prefer-template": true,
         "promise-function-async": true,
         "quotemark": [true, "single", "avoid-escape", "jsx-double"],
         "restrict-plus-operands": true,

packages/utils/src/abi_utils.ts

@@ -26,7 +26,7 @@ function parseEthersParams(params: DataItem[]): { names: ParamName[]; types: str
 
             const result = parseEthersParams(param.components);
             names.push({ name: param.name || null, names: result.names });
-            types.push('tuple(' + result.types.join(',') + ')' + suffix);
+            types.push(`tuple(${result.types.join(',')})${suffix}`);
         } else {
             names.push(param.name || null);
             types.push(param.type);
@@ -120,7 +120,7 @@ function splitTupleTypes(type: string): string[] {
     if (_.endsWith(type, '[]')) {
         throw new Error('Internal error: array types are not supported');
     } else if (!_.startsWith(type, 'tuple(')) {
-        throw new Error('Internal error: expected tuple type but got non-tuple type: ' + type);
+        throw new Error(`Internal error: expected tuple type but got non-tuple type: ${type}`);
     }
     // Trim the outtermost tuple().
     const trimmedType = type.substring('tuple('.length, type.length - 1);

packages/utils/test/abi_encoder/evm_data_types_test.ts

@@ -901,7 +901,7 @@ describe('ABI Encoder: EVM Data Type Encoding/Decoding', () => {
             // Construct args to be encoded
             // Note: There will be padding because this is a bytes32 but we are only passing in 4 bytes.
             const bytesLength = 40;
-            const args = '0x' + '61'.repeat(bytesLength);
+            const args = `0x${'61'.repeat(bytesLength)}`;
             // Encode Args and validate result
             const encodedArgs = dataType.encode(args, encodingRules);
             const expectedEncodedArgs =
@@ -993,7 +993,7 @@ describe('ABI Encoder: EVM Data Type Encoding/Decoding', () => {
             // Construct args to be encoded
             // Note: There will be padding because this is a bytes32 but we are only passing in 4 bytes.
             const strLength = 40;
-            const args = '0x' + 'a'.repeat(strLength);
+            const args = `0x${'a'.repeat(strLength)}`;
             // Encode Args and validate result
             const encodedArgs = dataType.encode(args, encodingRules);
             const expectedEncodedArgs =